164693872921 has 2 divisors, whose sum is σ = 164693872922. Its totient is φ = 164693872920.

The previous prime is 164693872919. The next prime is 164693872939. The reversal of 164693872921 is 129278396461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 121703997321 + 42989875600 = 348861^2 + 207340^2 .

It is a cyclic number.

It is not a de Polignac number, because 164693872921 - 2¹ = 164693872919 is a prime.

Together with 164693872919, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (164693872961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82346936460 + 82346936461.

It is an arithmetic number, because the mean of its divisors is an integer number (82346936461).

Almost surely, 2^164693872921 is an apocalyptic number.

It is an amenable number.

164693872921 is a deficient number, since it is larger than the sum of its proper divisors (1).

164693872921 is an equidigital number, since it uses as much as digits as its factorization.

164693872921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7838208, while the sum is 58.

The spelling of 164693872921 in words is "one hundred sixty-four billion, six hundred ninety-three million, eight hundred seventy-two thousand, nine hundred twenty-one".